File:NewcomenWattEngine.png

Summary

Update of the Newcomen steam engine by James Watt.

Figure 181 of textbook ^[1]

Description

.. The next great step in the development of the steam en- gine came through a Scotch in- strument maker, James Watt (1736-1819). He arranged a separate vessel for condensing the steam, as shown in figure 181. This condenser, (7, was connected with the cylinder through a valve V. When the piston had reached the top of the cylinder, the valve V was closed and V' was opened. Then the steam rushed from the cylinder into the condenser, which was kept cold and under less than atmospheric pressure. At first these valves V and V' had to be operated by hand, but later, it is said, a boy named Potter, whose job it was to turn these valves, connected the valve handles by cords to the beam ED in such a way that the machine became automatic.

In all these crude machines the steam simply furnished the vacuum, and atmospheric pressure did the work. Later, Watt made a machine with a closed cylinder and a piston that was pushed down as well as up by steam. By the use of a connecting rod and crank shaft, he contrived to change the back-and-forth motion of the piston to a rotary motion, and so made the steam engine available for many new uses. Within a few years the development of the steam engine revolutionized most lines of industry.

Reference